Rotary cutter device



pm 2%, @3L R. s. MCKEAGE ROTARY CUTTER DEVICE Filed July 12, 192s 4sheets-sheet 1 pri 28, MEL R. s. Mcm-:AGE

ROTARY CUTTER DEVICE Filed July 12, 192s 4 sheets-sheetv 2 4sheets-Sheet 5 if, l mml hx 7m B M@ pril 28, 1931. R, s, MCKEAGE ROTARYCUTTER DEvIcE Filed July l2, 1926 NBWN.

April 28, 1931. R, s, MCKEAGE ,803,068

ROTARY CUTTER DEVICE Filed July l2. 1926 4 Sheets-Sheet 4 NN www QN mwNH h Patented I,-pr. 28, 1931 UNITED STATES PATENT oEFicE ROBERT S.MOKEAGE, CICERO, ILLINOIS, ASSIGNOR TO SPEEDWAY MANUFACTURING COMPANY, FCHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS ROTARY CUTTER DEVICEApplication led July 12,

My improvements relate to rotary cutter devices, more particularlyrotary saws, p ro vided as portable hand tools and involving motors, asfor example and more especially,

s electric motors, for driving the cutter elements.

My object, generally stated, is to provide improvements in devices ofthis general type to the end that the device may be rendered w morecompact; be more readily manipulated; and protection be afforded to theoperator from injury by the cutter especially upon the disengagementofthe device from the work.

More specifically stated, certain of I ny objects are to provide for theshortening of devices of the character above referred to; t0 provide aguard device which shall in the disengagement of the device from theworlz following the cutting operation, automatically 2o become sopositioned that 1t will prevent the contacting of the cutter elementwith the 'operator and thus protect him from injury; to provide improvedgage means for limiting the depth of cut, and preferably toprovide 2osuch gage means for direct cooperation with' the guard controllingmeans; to provide for the engagement of the device with the uppersurface of the work, at a sufficiently large ar-ea thereof and solocated relative to the mass of the tool, as to ensure the operation ofthe cutting element in a plane at a right angle to the work 'to whichthe device is applied; to provide improvements in the guard device forthe upper portion of the cutting element to the end that thecutter-element may be rendered more readily accessible; to provide in adevice of the general character above referred to and equipped with anelectric motor controlled by a switch on the device, for readily andconveniently engaging, and disengaging, at will, from the switch proper,the manually operable switch-controlling lever; and other objects aswill be manifest from the following description.

Referring to the accompanying drawings :--l

Figure 1 is a view in side elevation of a rotary cutter deviceconstructed in accordance with my invention, the device being shown inthe position it assumes when conditioned 1926. Serial N'o. 121,881.

for operating on the work, one of the gaging means of the device beingshown in section. Figure 1n is an enlarged detail sectional view of aportion of the saw-guard, the section being taken at the line 1 on Fig.1 and viewed in the direction of the arrow. Figure 1b is an enlargedsectional detail take'n at the line 1b on Fig. 1 and viewed in thedirection of the arrow. Figure 2 is a plan view of the structure shownin Fig. 1, this view being taken n a plane normal to the body portion ofthe device. Figure 3 is a plan view of the slipp-er-plate at which thedevice engages, and slides along, the work to be operated on, thepivoted link rising therefrom being shown in section, with portions ofone of the gaging devices broken away. Figure 4 is a view in endelevation of the st-ructure shown in Fig. 3 and representing thestructure as viewed from the left-hand side of Fig. 3, with said gagingdevice omitted. Figure 5 is a section taken at the irregular line 5 5 onFig. 2 and viewed in the direction of the arrow, but with the partspositioned as shown in Fig. 1. Figure 6 is a detail, somewhat in thenature of a diagram, of the switch for the motor of the device and thecontrolling means therefor. Figure 7 is a broken sect-ion taken at theline 7-7 on Fig. 2 and viewed in the direction of `the arrows. Figure 8is a section taken at the line 8 8 on Fig. l and viewed in the directionof the arrows with the said gaging device omitted; and Figure r9, abroken sectional view taken at the line 9 on Fig. 7 and viewed in thedirection of the arrow.

According to the particular illustrated embodiment of my invention, thedevice nsV comprises a base-plate 10 upon which the cuttingelement andthe motor for operating the latter are mounted, this plate extendingforwardly beyond these parts and hingedly connected at its forward plate11 at which the device, in performing the cutting operation, rests on,and slides along, the work to be operated on, as for example a board tobe cut.

The cutter element, shown as a circular saw in the constructionillustrated, is represented at l2 and is rigidly secured to the outerend of a shaft 13 which extends transextremity with a versely throughthe forward compartment 14 of a casing 15, the rear compartment of whichis represented at 16. The shaft 13 is journalled at one end in a bearing17 provided in a wall of the casing 15 and at its opposite end, adjacentto the saw 12, in a ball-bearing 18 mounted in an opening 19 in theopposite side wall of the casmg, the casing at this pointpbeing providedwith an ann ar ring-like boss 20. The ball-bearing 18 is slidablyadjustable in the opening 19 in a direction lengthwise of the shaft 13and is backed by an'adjustable gland 21 which also is slidablelengthwise in the ring-boss 20 and is held in adjustable position withshims 21b interposed between the boss and gland, by screws 21u passingthrough this gland and screwin into the ring-boss. The shaft 13 is provied with a bevel gear 22 rigidly secured thereto by a nut 23 screwed uponthe shaft 13 and clamping it against an annular shoulder 24 on thisshaft. The inner ball-race of the bearing 18 flatwise abuts the adjacentface of the gear 22 and Vthe inner end of the gland 21 engages the outerface of the outer-race of this bearing 18 thus resisting movement of theshaft 13 to the right in Fig. 8 under the thrust exerted thereon throughthe gear 22, the bearingl 18 serving as a combined radial and thrustbearing, and the adjustable gland 21 permitting yof accurate adjustmentof the gear 22 relative to its driving intermeshing gear, hereinafterreferred to.

The motor represented at 28 for driving the saw 12 and which may be ofany suit' able type, is shown as an electric motor located within thecompartment 16, its field being represented at 29 and its rotatablearmature at 30, the armature being journalled at its shaft`31 in the endWalls of the compartment 16, by means of ball-bearings represented at32'and 33. The forward end of the armature shaft- 31, which is squaredas represented at 34, extends into the compartment 14 and telescopes, asshown, with a jack-shaft 35 which is journalled, at its forward end, inball-bearings 36 housed in a cup-shaped dust-cap 368L located in anopening 14b in the forward end wall 14 of the compartment 14. The shaft35 is provided with a pinion 37 meshing with a gear 38 rigidly connectedwith a shaft 39 journalled, at opposite sides of the gear 38, inball-bearings 40 and 41 supported,`respectively, in a bearing-boss 42 onthe casing and in an opening 14 in the forward wall 14a of thecompartment 14. The inner end of the shaft 39 is provided with a bevelpinion 43 meshing with the bevel gear 22 on the shaft 13, and properadjustment of the pinion 43 relative tothe gear 22 is effected by thegland-structure'41'l functioning as in the case of the gland 21.

The casing 15 is preferably formed of hollow main sections 44,45, 46 and47. The section 44, in which the motor above referred to is located, isof general cylindrical form with its forward end open and containing aperipheral series of apertures 48 radially aligned with anair-circulating fan 49 mounted on the armature shaft 31 and located inthe compartment 16 and operating to cause air to be drawn into thecompartment 16 through air-openings, hereinafterl referred to, inl thecasing-section 46 and be discharged through the apertures 48 to assistin maintaining the motor in cool condition. TheY rear end of-thecasing-section 44 is formed with a yoke-portion 50, in an opening 51u inthe cross-piece 5l in which a cupshaped dust-plug 52 confining thebearing 32, is located. The cross-'piece 51 serves as-a support for thebrushes of the motor and their binding posts, details of which areomitted from the drawings.

The casingFsection 45 is closed at its opposite ends, except for theopenings in which the bearings 33, 36, and 41 are located, the end wallsthus provided being represented at 54 and 55. The end wall 54 isperipherally grooved, as represented at 56, to adapt this wall-formingportion to be telescoped with the forward end of the casing-section 44,as. represented, these sections being secured together by screws 57passing through bosses 58 on the member 54 and into bosses 59 on thecasing-section 44. The casing-section 45 is provided, adjacent itsforward extremity, with a hand-knob shown as formed of a knob-portin 60secured, to an .upwardly-extending boss 61 formed as a part of thecasing section 45, by a screw 62 extending through this knob andscrewing into the boss.

The casing section 46 comprises a portion 66 of general cup-shape whichfits over the yoke 50 and against an annular flange 67 formed on thecasing-section 44 at the base of the yoke, the section 46 being rigidlysecured in position on the section 44, by screws 67 passing throughbosses 68 on the portion 66 and screwing intobosses 69 on the section44, the air-inlet openings hereinbefore referred'to, and represented at70, being provided in the section 46 as shown, the casingsection 46being formed with a hollow handgrip portion 71 which extends to onesidel of the longitudinal axis of the device and is open, as representedat 72, at its forward upper extremity.

The casing-section 47 which forms a housing for. the switch, hereinafterreferred to, and by which the operation of the motor is controlled, isformed of a hollow member osed position on the vcas' a oss 74 on thesection 44 and by a screw 75 passing'through a boss 76 on thecasing-section 46 and screwing into a boss]77 on the casing-section 47.The forward open end of the hand-grip portion 71, in the assembly ofthese various sections, lits the rear open end of the casin -section 47to form a continuation thereo as represented; the upper portion of thecasing-section 44 being formed with a portion, represented at 78, andpresenting a flat upper surface to form a bottom closure for theswitch-housing 47.

The switch for controlling the motor 28 and which may be of anydesirable construction, is represented generally at 79. The switch shownis of a type comprising the spaced pairs of contacts 88 and` 81 and arocking contact 82 adapted when swung in clockwise direction in Fig. 6to engage the contacts 80 and 81 thereby bridging the gap and closingthe circuit atthis point. The rocking contact 82 is connected with ayokeshaped member 83 interposed therebetween and connected at itscross-piece 84 with the lower end of a coil spring 85 the upper end ofwhich is connected with the cross-bar portion 86 of a rocking member 87journalled on stationary trunnions 88. The movable contacts 82 are movedinto and out of engagement with the cooperating stationary contacts by asnap action produced by the spring 85 in the rocking of the member 87,in its movement in both directions, to carry the point of connectionbetween it and the spring 85 beyond a line passing through thislast-referred-to point of connection, the axis about which the yoke -83swings and the point ofconnection between the spring 85 and the yoke,the yoke 83 in its swinging movements referred to, engaging terminalstops (not shown) which limit the rocking of this yoke in bothdirections.

The device also comprises means, operated by the operator, forcontrolling the switch just described, these means comprising a link 89pivotally connected at its rear end, as indicated at 90, to a link 91pivoted to the casing-section 66, as represented at 92, the forward endof the link 89 containing a downwardly opening recess 93 at which thislink is adapted to straddle the cross-piece 86 and in which positionthis link is held by a flat spring 94 connected at its rear end, asrepresented at 95, to the top of the casing-section 47 and bearing,under spring-tension at its forward end downwardly against the link 89,the switch being operated into and out of circuit closing position, byshifting the link 89 in opposite directions. The switchcontrollingmechanism also comprises a rod 96 which slides in an opening 97 in therear end of the grip 71, which latter carries a guard-rib 71a, theforward end of the rod 96 being downwardly curved, as represented at 98,and pivotally connected at 99 w1th the link 91 between the pivots 90 and92. The bar 96 carries a trigger element 100 rigidly connected therewithand movable, with the rod 96, in a slot 101 in the grip 71, the trigger100 extending into the linger-opening 102 .in the hand-gri portion 71,in position to be actuated by the forenger of the hand grasping the grip71. A coil-spring 103 surrounding the rod 96 and interposed between thetrigger 100 and a Wall of the hand-grip 71, serves to normally hold theswitch-operating mechanism and the switch, in the positions shown inFigs. 5 and 6, in which the circuit of the motor is broken, and toautomatically return this bar to circuit-open position following theclosing of the switch by pressing rearwardly on the trigger 100, and thereleasing of the operators grip thereon, the spring 94 ensuring theengagement of the ink 89 with the switch mechanism at all imes.

The current-conducting wires, for supplyking current to the motor, andwhich are located in the sheath 104, lead into the interior of thehand-grip 71 through an opening 105 therein, one of these wiresrepresented at 106 and 107, connecting with the stationary contact 80and the other thereof leading to one of the binding posts of the motor.The oiher stationary contact 81 connects by a wire 108 with the otherbinding post of the motor.

The base plate 10, which is slotted, as represented at 109, to permitthe saw 12 to proJect downwardly therethrough as shown, is provided witha guard 110 for covering that portion of the saw which extends abovethis plate, to protect the operator from contact with the saw. Thisguard is in the form of a substantially semi-circular hollow casingwhich straddles the upper portion of the saw in spaced relation theretoand is formed of a curved peripheral-wall-forming' strip 111 having itsends outwardly turned, as reperesented at 112, at which it is secured tothe base-plate 10 by screws 113. The guard also comprises asubstantially semi-circular plate 114 permanently connected with thewall portion 111, as by means of angle-bars 115 located in the interiorof the guard and secured to the strip 111 and the plate-portion 114 asby spot-Welding them thereto, the plate 114 containing a slot 116 atwhich it straddles the shaft 13. The outer-side-wall-forming portion ofthe guard is in the form of a substantially semi-circular plate -117containing a slot 118 at which it straddles the shaft 13, the plate 117being releasably held against the outer edge of the wall-portion 111, byreleasably interlocking the plate 117 at its lower end with the curvedstrip 111 and providing a fastening device on the strip 111 ywhichreleasably engages the up er end of the plate 117. The interlock reerred to is provided by forming undercut-lugs 119 on the outer edge ofthe strip 111 and slots 120 in the plate 117 whichv receive the lugs 119130 with the lower edges of the slots extending into the undercutportions, when the plate 117 is applied to position on the stationarypart of the guard. The fastening device referred to comprises a'yoke 121rigidly secured to the upper part of the strip 111 and in which aspindle` 122 is journalled, the spindle having a knurled disk 122* rigidthereon and located betweenthe arms of the yoke 121 but of a thicknessless than the width of they space between the arms of the yoke, wherebythe spindle may have limited lengthwise movement in the yoke 121.V Theouter end of the spindle 122 is screw threaded at 122b to screwA into athreaded opening 117 in a 111gr 117b on the plate 117 when this plate isapplied to position as stated, and securely hold this plate in place. Itwill be understood from the foregoing that the plate 117 may be readilyremoved from the stationary part of the guard of which it forms a partand thereby render the saw 12 readily accessible for removal from theshaft 13 without disturbing the fastening devices for the stationarypart of the guard. vThe guard is preferably steadied in position on thebase 10 bya brace-bar 10El which. is connected at its outer angularend-portion 10b with the plate 114 and at its opposite end with thecasingsection 4,5, as by one of the screws 47 extending therethrough.

The device also comprises means for gaging the depth to which the sawenters the work, and means for reventing the contacting of the lowerportion of the saw with the operator following the disengagement of thedevice from the work; these means comprising the following describedmechanisms:

The plate 11 which contains a slot 123 in registration with the saw 12and through which the latter extends when the device is conditioned forcutting, is hingedly connected at its forward end with the forward endof the base-plate 10 by the nested yoke-members 124 and 125 provided onthe base plate 10 and the plate 11, respectively, and connected togetherby a hinge-pin 126. The plate 11 is provided at its rear end with a bar127 extending transversely thereof and rigidly secured thereto andhaving an upwardly-turned portion 128 at oney end equipped with a screw129 having a head 130 at its outer end and a flange 131\between itsends, this pin extending through, and

forming a pivot for, the lower end of a link 132, which is yieldinglypressed in clockwise direction (Fig. 1) by a s ring 133 encircling thepin 129 between the head 130 and flange 131 and connectedl at its outerend `with this pin and at its inner, free, end,

lapped 4across the edge of the link 132, tending to swing the latter tothe right in Fig. 1.

The link 132 contains a lslot 134 extending lengthwise thereof with alateral recess 135 at its upper end affording a shoulder 136 for apurpose hereinafter described. The baseplate 10 is provided with a bar137 extendmg crosswise thereof and having an upturned end 138l carryinga pin 139 extending into the slot 134 and adapted to enter the recess135 and engage with the shoulder 136 under the conditions, and for thepurpose, hereinafter described, the pin 139 having a mutilatedcollar-portion 139 presenting a Hat surface 139". The link 132 isprovided with a aging device, represented generally at 140,

or cooperation with the pin 139 to regulate the depth of cut, thisdevice comprising a screw 141 extending through the slot 134 and screw141 extending through the slot 134 and provided at one end with a block142 presenting a flat upper surface andl at its opposite vend with aclamping thumb-nut 143 for vertical adjustment on the link 132, a washer144 being confined on the screw 141 between the nut 143 and the link132. As the block 142 is located directly below the collar 139" itserves as a stop for the latter to limit the downward swinging of thebase-plate 10 and the parts carried thereby, at the hinge 126 therebyregulating the rdepth pf cut, it being understood that by adjusting thedevice 140 up or down on the link 132 the position of the base-plate 10relative to plate 11, may be varied as desired.

It may be here stated that in the use of the device, as for example tosaw a board, the device is appliedgto the work to rest at its plate 11thereon and then moved across the work, the weight of the plate l0 andthe parts carried thereby, augmented or not, as desired, by downwardpressure applied by the operator while grasping the handle 6'0 with onehand and the handle-grip 71 with the other. So long `as the plate 11 issupported, as by engaging the work as stated, the weight of the plate 10and the parts carried thereby is supported by the plate 11. As soon,however, as the plate 11 becomes unsupported, as for example in thedisengagement of the device from the work bein cut, the plate 11 is freeto swing downwar ly at its hinge-connection 126 with the plate 10, thelink 132 in this movement lowering until the recess 135 is opposite thepin 139 whereupon the spring 133 swings the link 132 in clockwisedirection in Fig. 1 to cause this recess to receive the pin and therebylock the plate 11v in the downwardly-swung position stated in which itextends beyond the lowermost' edge of the saw 12 thereby preventing therotating saw from striking the leg of the operator in case the operatorpermits the device to lower to such position. The parts just referred toremain in the spread condition stated, until the should-er 136 on thelever 132 isdisengaged from the pin 139, by swinging the lever 132 incounterclockwise direction in Fig. 1. The means shown for this purposecomprise a bar 145 slidable los in guides 146 and 147 secured to theplate 114 and yieldingly pressed, by a spring 148, in a direction tohold a pin 149 on this bar against the guide 147. The rear end of thebar 145 is provided with a lip 150 which extends crosswise of the link132 and with which it engages, to release the shoulder 136 from the pin139, when the 'bar 145 is shifted rearwardly, as, for example by theoperator pressing rearwardly against a lip 151 extending laterally fromthis bar'at the forward end thereof.

The device also comprises means for guiding the device in astraight-line path dur-v ing .the cutting operation, these meanscomprising a depending guide-lip 152 carried by the rear end of theplate 11 in line with the saw 12, whereby this lip, in the bodilymovement of the device, slides in the kerf produced by the saw 12 andensures a straight-line cut. The lip 152 isshown as provided on the endof a plate 153 flatwise secured to the upper surface of the plate l1, asby screws 154, the plate 11 being slotted at 155 to receive the lip 152.

Means for gaging the distance of the cutl -from a predetermined line, asfor example from an end edge of the work, or a cleat, or

Ythe like, secured to a face of the work, are

provided, these means comprising an anglear 156 connected with the outerends of parallel cross-arms 157 which overlie the plate 11 and slide instrap guides 158 secured to this plate, these arms being held inadjusted position by nuts 159 which screw upon the upper threaded endsof studs 160 fixed in the plate 11 and down against the upper exibleportions of certain of the straps 158. If desired the gage device formedof the plate 156 and arms 157 may be positioned to extend at either ofthe opposed side edges of the plate 11 with its vertical flange 161extending either upwardly or downwardly.

The feature of providing the switch-actuating lever 89 as described andwhich is held in engagement with the switch by the Y spring 94, is ofadvantage as it may be readily swung clear of the switch to render thecutter shaft from said drive shaft engaging l with said drive shaft atthe other side of said cutter shaft and comprising an intermediate shaftand gearing connecting said -intermediate shaft to said first andsecondnamed shafts.

ROBERT S. MGKEAGE;

latter accessible as for example for repairing, upon disengaging thehousing section 47 from the section 44.

The feat'ure of providing a wide bearing area at which the device slidesover the` work, with the motor and other operating parts mounted thereonin centralized position is also of advantage in that it facilitates themanipulation of the device and ensures the desired straight-linemovement thereof, and the operation of the cutter at a predeterminedangle to the plane of the work.

While I have illustrated .and described a particular constructionembodying my invention I do'not wish to be understood as intending tolimit it thereto, as the samemay

